Characterization of bovine serum albumin glycated with glucose, galactose and lactose

The non-enzymatic reaction between reducing sugars and proteins, known as glycation, has received increased attention from nutritional and medical research. In addition, there is a large interest in obtaining glycoconjugates of pure well-characterized oligosaccharides for biological research. In this study, glycation of bovine serum albumin (BSA) by d-glucose, d-galactose and d-lactose under dry-heat at 60°C for 30, 60, 120, 180 or 240 min was assessed and the glycated products studied in order to establish their biological recognition by lectins. BSA glycation was monitored using gel electrophoresis, determination of available amino groups and lectin binding assays. The BSA molecular mass increase and glycation sites were investigated by mass spectrometry and through digestion with trypsin and chymotrypsin. Depending on time and type of sugar, differences in BSA conjugation were achieved. Modified BSA revealed reduction of amino groups' availability and slower migration through SDS/PAGE. d-galactose was more reactive than d-glucose or d-lactose, leading to the coupling of 10, 3 and 1 sugar residues, respectively, after 120 minutes of reaction. BSA lysines (K) were the preferred modified amino acids; both K256 and K420 appeared the most available for conjugation. Only BSA-lactose showed biological recognition by specific lectins

Cápsulas de polvo de arándano como propuesta nutracéutica para mejorar la bioaccesibilidad de compuestos fenólicos

El arándano (Vaccinium corymbosum L.) posee un alto contenido de compuestos fenólicos los cuales han sido estudiados principalmente por su actividad antioxidante, antiobesogénica, antiinflamatoria, entre otras. Objetivo. Evaluar el efecto de la digestión gastrointestinal in vitro sobre la bioaccesibilidad de compuestos fenólicos y actividad antioxidante de una formulación nutracéutica de arándano (cápsula), comparado con arándano fresco y polvo. Materiales y métodos. Se obtuvieron extractos metanólicos de muestras de arándano fresco y liofilizado y se determinó su contenido de fenoles, flavonoides y antocianinas totales, así como también actividad antioxidante. Se llevó a cabo un ensayo de simulación de digestión gastrointestinal para evaluar la bioaccesibilidad de los compuestos fenólicos presentes en las muestras. Resultados. Los resultados mostraron que la digestión gástrica de arándano en polvo y en cápsula promovió una mayor bioaccesibilidad de fenoles (42% y 40%), flavonoides (52% y 33%) y antocianinas (45% y 40%) comparado con digestos de arándano fresco. Posterior a la digestión intestinal, la bioaccesibilidad de fenoles (63%) y flavonoides (67%) fue mayor en la cápsula de arándano comparada con su contraparte arándano en polvo. Las condiciones de digestión intestinal afectaron negativamente la bioaccesibilidad de las antocianinas independientemente del tipo de muestra evaluada. Conclusión. Las condiciones de digestión gástrica promueven una mayor estabilidad de los compuestos fenólicos en arándano en polvo y en cápsula lo que pudiera ser relevante para el mantenimiento de un ambiente antioxidante a este nivel. Las condiciones de digestión intestinal afectaron de manera particular a los compuestos fenólicos de arándano fresco y polvo, pero no a la cápsula, lo que puede sugerir que el encapsulamiento protegió de las condiciones alcalinas a los fenoles presentes. Se sugieren estudios posteriores sobre absorción in vitro de los componentes remanentes en intestino y sus posibles efectos sobre biomarcadores de estrés oxidativo en modelos in vivo.Blueberry (Vaccinium corymbosum L.) has a high content of phenolic compounds which have been studied mainly for their antioxidant, antiobesogenic, anti-inflammatory activity, among others. Objetive. The objective of the present study was to evaluate the effect of in vitro gastrointestinal digestion on the bioaccessibility of phenolic compounds and antioxidant activity of a nutraceutical formulation of blueberry (capsule), compared to fresh and powder blueberry. Materials and methods. Methanolic extracts of fresh and lyophilized blueberry were obtained and determined its total phenols, flavonoids, anthocyanins content, as well as antioxidant activity. A gastrointestinal digestion simulation test also was carried out to assess the bioaccessibility of the phenolic compounds found in samples. Results. The results showed that gastric digestion of powder and capsule blueberry promoted greater bioaccessibility of phenols (42% and 40%), flavonoids (52% and 33%) and anthocyanins (45% and 40%), compared to fresh blueberry digests. After intestinal digestion, the bioaccessibility of phenols (63%) and flavonoids (67%) was higher in the blueberry capsule compared to its powdered blueberry counterpart. The intestinal digestion conditions negatively affected the bioaccessibility of anthocyanins regardless of the type of sample evaluated. Conclusion. Gastric digestion conditions promote greater stability of phenolic compounds in powdered and capsule blueberries, which could be relevant for the maintenance of an antioxidant environment at this level. The intestinal digestion conditions particularly affected the phenolic compounds of fresh and lyophilized blueberry, but not the capsule, which may suggest that encapsulation protected the phenols present from alkaline conditions. Further studies on in vitro absorption of the remaining components in the intestine and their possible effects on oxidative stress biomarkers in in vivo models are suggested

Management of freezing rate and trehalose concentration to improve frozen dough properties and bread quality

Abstract Bread is one of the most consumed foods in the world, and alternatives have been sought to extend its shell life, and freezing is one of the most popular methods. The purpose of this study was to evaluate the effect of freezing rate and trehalose concentration on the fermentative and viscoelastic properties of dough and bread quality. Dough was prepared and trehalose was added at three concentrations (0, 400, 800 ppm); dough was pre fermented and frozen at two freezing rates then stored for 42 days. Frozen dough samples were thawed every two weeks. CO2 production and elastic and viscous modulus were determined. In addition, bread was elaborated and specific volume and firmness were evaluated. High trehalose concentrations (400 and 800 ppm) produced dough with the best viscoelastic and fermentative properties. Greater bread volume and less firmness were observed when a slow freezing rate (-.14 °C/min) was employed

Management of freezing rate and trehalose concentration to improve frozen dough properties and bread quality

Abstract Bread is one of the most consumed foods in the world, and alternatives have been sought to extend its shell life, and freezing is one of the most popular methods. The purpose of this study was to evaluate the effect of freezing rate and trehalose concentration on the fermentative and viscoelastic properties of dough and bread quality. Dough was prepared and trehalose was added at three concentrations (0, 400, 800 ppm); dough was pre fermented and frozen at two freezing rates then stored for 42 days. Frozen dough samples were thawed every two weeks. CO2 production and elastic and viscous modulus were determined. In addition, bread was elaborated and specific volume and firmness were evaluated. High trehalose concentrations (400 and 800 ppm) produced dough with the best viscoelastic and fermentative properties. Greater bread volume and less firmness were observed when a slow freezing rate (-.14 °C/min) was employed

Bioprocessing of wheat (Triticum aestivum cv. Kronstad) bran from Northwest Mexico: effects on ferulic acid bioaccessibility in breads

Evaluating the biological potential of wheat grain cultivated in northwestern Mexico is important because it mainly varies according to the cultivar and production area. The aim of the present study was to evaluate ferulic acid (FA) bioaccessibility in breads supplemented with bioprocessed bran. Bran that was bioprocessed with xylanase enzyme (EB), yeast fermentation (FB), and a combination of both treatments (FEB) showed a higher total phenol content and antioxidant capacity compared with native bran (NB), and the majority of these components were found in a bound fraction. For NB and bioprocessed bran, FA was found at higher levels compared to the other hydroxycinnamic acids evaluated. Bioprocessing increased the free FA content six-fold compared to NB. The % bioaccessibility of FA in different breads increased in the following order: FEB<NB<FB<EB. The addition of bioprocessed bran is may be the simple way to increase the amount of bioactive compounds in a bread product

Estabilidad oxidativa y contenido de compuestos fenólicos durante el almacenamiento del salvado de sorgo (Sorghum bicolor (L.) Moench) extrudido

Sorghum bran has a high antioxidant capacity due to the high concentrations of phenolic compounds. During decortication of the sorghum grain to obtain the bran, lipid oxidation reactions may occur that cause deterioration in its quality. To avoid this, thermal stabilization processes such as extrusion are used. The objective of this work was to evaluate chemical, stability of phenolic compounds and antioxidant capacity changes of extruded red sorghum bran. Raw sorghum bran (SC) and extruded (SE) sorghum bran were stored for 42 days and chemical (peroxide index, pH, free fatty acid), phenolic compounds, antioxidant capacity and phenolic acids determinations were carried out. The type of bran was the factor that most affected results of the chemical evaluations. The SE showed greater stability in quality than the SC, which had significant changes in free fatty acid and peroxide index. The content of phenolic compounds and the antioxidant capacity of both types of bran were not modified by the effect of storage. However, the SE presented higher levels of both parameters than the SC. The sorghum bran extrusion process retards enzymatic oxidation of lipids and improves the extraction of phenolic compounds.El salvado de sorgo posee una alta capacidad antioxidante debido a su elevado contenido de compuestos fenólicos. Durante el decorticado del grano para la obtención del salvado, pueden presentarse reacciones de oxidación lipídica que deterioran su calidad. Para evitar esto, se emplean procesos de estabilización como la extrusión. El objetivo de este trabajo fue evaluar los cambios químicos en los compuestos fenólicos y la capacidad antioxidante del salvado de sorgo rojo extrudido. Los salvados de sorgo crudo (SC) y extrudido (SE) se almacenaron durante 42 días para poder evaluar los cambios químicos (índice de peróxidos, pH y ácidos grasos libres), en los compuestos fenólicos, su capacidad antioxidante y la presencia de ácidos fenólicos. El tipo de salvado fue el factor que más afectó los resultados de las evaluaciones químicas. La calidad del SE fue más estable en comparación con la del SC, el cual tuvo cambios significativos de ácidos grasos libres e índice de peróxidos. El contenido de compuestos fenólicos y la capacidad antioxidante de ambos tipos de salvado no se modificaron significativamente (p > 0.05) por efecto del tiempo de almacenamiento, sin embargo, el SE presentó niveles superiores en compuestos fenólicos y capacidad antioxidante que el SC. El proceso de extrusión del salvado de sorgo retarda la oxidación enzimática y mejora la extracción de los compuestos fenólicos

Preparation, Characterization and Release of Urea from Wheat Gluten Electrospun Membranes

Homogeneous and thin porous membranes composed of oriented fibers were obtained from wheat gluten (WG) using the electrospinning technique. SEM micrographs showed an asymmetric structure and some porosity, which, in addition to a small thickness of 40 mm, are desirable characteristics for the membranes&amp;#8217; potential application in release systems. The membranes were loaded with urea to obtain pastilles. FT-IR and DSC studies confirmed the existence of interactions via hydrogen bonding between urea and WG proteins. The pastilles were studied as prolonged-released systems of urea in water. The release of urea during the first 10 min was very fast; then, the rate of release decreased as it reached equilibrium at 300 min, with a total of &amp;#187;98% urea released. TGA analysis showed that the release system obtained is thermally stable up to a temperature of 117 &amp;#176;C. It was concluded that a prolonged-release system of urea could be satisfactorily produced using WG fibers obtained by electrospinning for potential application in agricultural crops